patrols use a GL4 oil, but GL5 is more common . if you read the labels some GL5 oils say they are compatible with GL4 but some people have had issues with there gear boxes when they used them . nissan specifies GL4 . some that have used GL5 say it's ok , but others that have used it have had problems which went away when they went back to a GL4 oil . i have recently changed the gearbox oil on my patrol , i used synthetic nulon w75/85 GL4 . iv'e had the car from new and the gears were always notchy but now is mutch smoother